export function calculateDistance(lat1, lon1, lat2, lon2) {
	const R = 6371; // 地球半径，单位：千米
	const dLat = deg2rad(lat2 - lat1);
	const dLon = deg2rad(lon2 - lon1);
	const a =
		Math.sin(dLat / 2) * Math.sin(dLat / 2) +
		Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) *
		Math.sin(dLon / 2) * Math.sin(dLon / 2);
	const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
	const distance = R * c; // 返回距离，单位：千米
	return distance;
}

// 辅助函数，将角度转换为弧度
export function deg2rad(deg) {
	return deg * (Math.PI / 180);
}